The Boeing cargo plane veered off the runway during landing early Monday morning, then hit a security patrol car and skidded into the sea.

It was one of the most serious incidents since the airport began operations in 1998.

Two security staff were killed in the incident, with authorities saying they had been in a safe position "outside the runway area".

Airport Authority Hong Kong said Saturday one of the engines and the landing gear have been salvaged along with data recorders.

The city's transport and logistics bureau said it will release a preliminary investigation report within one month.

Authorities added that the American and Turkish civil aviation accident investigative agencies, and experts from Boeing, are participating in the investigation.

Emirates Airlines said the plane was on a short-term lease from the Istanbul-headquartered Act Airlines, which operated the aircraft.